Propeller control mechanism



March 27, 1962 c. c. COVERT 3,025,740

PROPELLER CONTROL MECHANISM Filed July 12, 1960 4 Sheets-Sheet 1 It g I N VEN TOR.

ga/w)? 6: ("ox er) H15 ATTOR/Vf March 27, 1962 c. c. COVERT 3,025,740

PROPELLER CONTROL MECHANISM I Filed July 12, 1960 4 4 Sheets-Sheet 2 s l 4 g g N INVENTOR.

Q\ g 011/1)? 6: @vzfi il: 5 MI gawk 1s ATTORNEY C. C. COVERT March 27, 1962 Filed July 12, 1960 INVENTOR. (ah 1'22 C ("or a2) BY HIS ATTOAIMEY 4 Sheets-Sheet 4 Filed July 12, 1960 INVENTOR. a/Vi)? C: (bl K BY Warm HIS ATTORNEY 3,926,740 PERGPELLER (IUNTRGL MECHANISM Calvin C. Covert, Dayton, Uhio, assignor to General Motors Corporation, Detroit, Mich, a corporation of Delaware Filed July 12, 1960, er. No. 42,392 18 Claims. (Cl. 74-395) This invention pertains to variable pitch propellers, and particularly to an improved system for transmitting control intelligence between stationary and rotatable components of a variable pitch propeller.

In copending application Serial N 0. 766,611, filed October 10, 1958, in the name of Conn et al., and assigned to the assignee of this invention, a variable pitch propeller is disclosed in which a regulator assembly is attached to the rear of a propeller hub supported on a stationary shaft and driven through a hollow shaft which is connected to the hub at the front end thereof. This invention relates to control means for a propeller of the type disclosed in the aforementioned copending application wherein the regulator assembly is mounted in front of the propeller hub and the hub is connected to the input shaft at the rear thereof. Accordingly, among my objects are the provision of an improved control system for transmitting intelligence from a stationary bearing housing to a rotatable regulator assembly mounted in front of the propeller hub; the further provision of means for transmitting control intelligence between relatively rotatable components of the propeller assembly; and the still further provision of means for transmitting control intelligence mechanically from a stationary bearing housing adjacent the rear of the propeller hub to a rotatable regulator assembly mounted in front of the propeller hub.

, The aforementioned and other objects are accomplished in the present invention by converting rotary input movement to rectilinear movement between relatively rotatable members, and converting rectilinear movement to rotary movement of a shaft extending centrally through the propeller hub. Specifically, the propeller comprises a hub having a plurality of blades journalled therein for rotation about their longitudinal axes to different pitch positions. The hub is supported for rotation by a bearing assembly located to the rear thereof and arranged within a stationary bearing housing. The propeller is of the type including a hydraulic servo motor for adjusting the pitch position of the propeller blades, the pitch changing motor being controlled by a hydraulic system contained Within the regulator assembly attached to the front of the propeller hub so as to rotate therewith.

The propeller may be operable in the regimes of governed speed forward thrust, governed speed reverse thrust, beta, or manually selected blade angles, feathering and reverse. In addition, propeller operation may be synchronized with operation of other propellers in the governed speed forward thrust regime. Accordingly, the propeller includes three mechanical inputs, namely, a condition lever, a feathering lever and a synchronizing lever. These levers are connected through suitable linkages to crank arms attached to radially extending shafts supported in the stationary bearing housing. The three shafts, in turn, are connected by internal crank arms to bellcrank assemblies disposed within the stationary bearing housing. The bellcranks have mechanical slip ring connections with rings connected to rotate with the propeller hub but capable of axial movement relative thereto.

The three rings disposed within the stationary bearing housing are drivingly connected with shafts extending inverted to rotation of the internally mounted shafts which are connected to high lead screws having threaded engagement with control nuts located within the regulator assembly. The control nuts arranged within the regulator assembly are likewise arranged for axial movement relative thereto, and are connected by suitable linkage means to the various control valves of the hydraulic system. Accordingly, movement of the input levers is transmitted between the relatively rotatable components of the propeller assembly from the rear of the propeller hub, through the propeller hub to the various control valve assemblies disposed within the front mounted regulator.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

in the drawings:

FIGURE 1 is a fragmentary View, partly in section and partly in elevation, of a propeller embodying the control mechanism of the present invention.

FIGURE 2 is an enlarged fragmentary view of a portion of the propeller shown in FIGURE 1, partly in section and partly in elevation, depicting the center mounted control.

FIGURE 3 is an enlarged, fragmentary sectional View taken along line 33 of FIGURE 2.

FIGURE 4 is a schematic view depicting the manner in which control intelligence is transmitted to the front mounted regulator assembly.

With particular reference to FIGURES l and 2, a propeller is shown including a hub til having a plurality of propeller blades 12 journalled therein for rotation about their longitudinal axes to different pitch positions. The hub ill includes an integral annular extension 14 at the rear thereof which projects through a substantially frusto conical stationary bearing housing, or support, in. The annular extension portion 14 of the hub 10 is rotatably journalled in the housing 16 by spaced front and rear support bearings, a portion of the front support bearing being depicted by numeral 1% in FIGURE 2. The end of the annular extension 14 is splined at Zil for driving connection with a prime mover driven input shaft.

A regulator reservoir assembly 22 is attached to the front of the propeller hub Iii for rotation therewith and contains a plurality of pumps and valves constituting a part of the hydraulic system for controlling the pitch position of the propeller blades 12. An annular slip ring assembly 24 and a plate-type slip ring assembly 26 are attached to the hub to for supplying electric power between relatively rotatable parts of the propeller assembly. The regulator assembly 22 and the major portion of the hub in are enclosed by a spinner assembly 28 having fairing islands 30 through which the shanks of the blades 12 project.

As seen in FIGURES 1 through 3, a portion of the annular hub extension 14 disposed within the stationary housing 16 has a set of external straight spline teeth 32. The straight splined portion of the hub extension is encircled by three rings, namely, a condition ring 3d, a feathering, or negative torque signal, ring 36, and a synchronizing ring 38. The condition ring 34 has four circumferentially spaced rearwardly axially extending fingers 4% having internal straight spline teeth 42 mating with the external straight spline teeth 32. on the hub extension 14. Similarly, the feathering and synchronizing rings, 36 and 38, respectively, have four circumferentially spaced fingers 4.4 and 2-6, respectively, extending axially forward and nested between the fingers 46. The fingers 44 have internal straight spline teeth 43 mating with external straight spline teeth 32, and the fingers 46 have internal straight spline teeth 5d mating with external straight spline teeth 32. The rings 34, 36 and 33 are, therefore, connected to rotate with the hub extension 14 although capable of axial movement relative thereto. Moreover, each ring is capable of axial movement independent of the other rings due to the nesting relation of the axially extending fingers. Moreover, the rings 36 and 38 are radially spaced from the hub extension 14 so that the fingers 41 of the ring 34 can move through the rings 36 and 38, and the fingers of the synchronizing ring 38 can move through the ring 36.

One of the axially extending fingers attached to each ring 34, 36 and 33 has a toothed edge constituting a rack, the racks being indicated by numerals 52 on one of the fingers 4t}; 54 on one of the fingers 44; and 56 on one of the fingers 46. A pinion supporting ring, or annulus, 58 encircles the hub extension 14 and is located between the condition ring 34 and the feathering ring 36. The pinion ring 58 is radially spaced from the hub extension 14, as clearly shown in FIGURE 3, so as to permit axial movement of the fingers relative thereto.

The support for the pinion ring 58 comprises three stub shafts 60, 62 and 64 extending radially through the hub extension 14, these shafts being journalled therein by sleeve bearings 66, 68 and 70, respectively. The stub shafts 611, 62 and 64 have pinion gears 72, 74 and 76, respectively, drivingly connected adjacent the outer ends thereof, the outer ends of the shaft being journalled by ball bearing assemblies, one of which is indicated by numeral 78 in FIGURE 2, in the pinion ring 53. The ball bearing assemblies coaxially support the pinion ring 38 in spaced relation relative to the hub extension 14.

The pinion gear 72 meshes with the rack 52; the pinion gear 74 meshes with the rack 54; and the pinion gear 76 meshes with the rack 56. Accordingly, upon reciprocation of the condition ring 34, rotation will be imparted to the pinion gear 72 and its shaft 611 about the axis of the shaft 69. Similarly, upon reciprocation of the feathering ring 36, rotation will be imparted to the pinion gear 74 and to the shaft 62, while reciprocation of the synchronizing ring 38 will impart rotation to the pinion gear '76 and its shaft 64.

The rings 34, 36 and 38 are formed with integral upstanding shoulders, or tongues, 35, 37 and 39, respectively. Since the inputs to the control rings 34, 36 and 38 are all identical, it is deemed suflicient to describe only one such input. Accordingly, as shown in FIGURE 1, the tongue 35 on the condition ring 34 is received by a complementary groove in a shoe 80 attached to one end of a bellcrank 82. The bellcrank 82 is pivotally supported by an intermediate pin 84 carried by a bracket 86 attached to the bearing housing 16. The bellcrank 82 is formed as a clevis with the bracket located between spaced portions thereof. The other end of the bellcrank 82 is pivotally connected by a pin 88 to the outer end of a crank arm 90. The crank arm is attached to a shaft 32 extending through the housing 16 and having a second crank arm 94 attached thereto. The outer end of the crank arm 34 is connected by a pin 96 to a reciprocable control rod 98.

It will be apparent that upon reciprocation of the control rod 98, angular movement will be imparted to the crank 94, the shaft 92 and the crank 90 so as to impart angular movement to the bellcrank 82. The bellcrank, in turn, will impart rectilinear movement to the control ring 34 through the shoe 80 which engages the tongue 35 thereof, irrespective of whether the propeller is or is not rotating. In this manner, control intelligence is transmitted between the stationary housing 16 and the rotatable control ring 34. Control intelligence is imparted to the control rings 36 and 38 in a similar manner.

Referring again to FIGURES 2 and 3, the inner ends of shafts 6t 62 and 64 have bevel gears 1%, 1112 and 104 attached to the inner ends thereof, the bevel gears 16!), 102 and 104 meshing respectively with bevel gears .106, 1118 and 111) attached to shafts 112, 114 and 116, re-

spectively, journalled in an annular housing 118 located internally of the hub extension 14. The housing 118 is located relative to the hub extension 14 by an internal annular shoulder 120 on the extension 14, one end of the housing 118 engaging one side of the shoulder 120, the housing being bolted to a ring 122 which engages the other side of the shoulder 120, the bolts being indicated by numerals 124 in FIGURE 3.

As the means for transmitting control intelligence from the stub shafts 112, 114 and 116 to the front mounted regulator assembly 22 are identical, it is deemed suflicient to describe only the means associated with the condition ring 34. Thus, as seen in FIGURE 2, the stub shaft 112 is drivingly connected to one end of a shaft 126 which extends axially through the hub 11), and the outer end of which is connected by straight splines 128 and a cross pin 13%) to a coupling 132 journalled in the regulator assembly housing. The coupling 132 contains a coil spring 134 which acts on the end of the shaft 126 for maintaining the bevel gears 106 and 1110 in driving engagement. The coupling 132 is in turn connected by straight splines 136 to a high lead screw 138 which extends to the regulator assembly. The high lead screw 133 is journalled adjacent its end by ball bearing assemblies 140 and 142 supported by the regulator assembly housing, and threadedly engages a nut, or control member 144. As seen in FIGURE 1, the nut 144 is connected to one end of link means 146, the link means being adapted to actuate a control valve within the regulator assembly. Since the linkage means 146, the nut 144 and the screw shaft 138 all rotate with the propeller hub, it will be appreciated that control intelligence will only be supplied to the linkage means 146 due to rotation of the screw shaft 138 about its own axis relative to the propeller hub.

With reference to FIGURE 4, operation of the control mechanism for transmitting mechanical movement between relatively movable parts of the propeller assembly will be described. In FIGURE 4, the reciprocating input control rod 98 is shown connected to a pivotally movable lever 148. Moreover, the control rod 98 is shown schematically as being directly connected to the bellcrank 82. Upon movement of the lever 148, the control rod 98 will pivot the bellcrank 82 so as to effect axial movement of the control ring 34. Axial movement of the control ring 34 will impart rotation to the pinion gear 72 through the rack 52 on one of the fingers 40. Rotation of the pinion gear 42 will impart rotation to the rotary shaft 126 through the meshing bevel gears 100 and 106 which will in turn rotate the high lead screw 138 so as to reciprocate the nut 144 within the regulator assembly. The nut 144 will, in turn, actuate the control valve through the linkage means 146.

It is pointed out that with the improved control mechanism of the present invention, mechanical input signals can be transmitted between relatively rotatable components of the propeller assembly through the hub to a front mounted regulator assembly. By mounting the regulator assembly in front of the propeller hub, the propeller drive can be through the rear thereof thereby enabling the propeller assembly to be nose mounted on the stationary support structure.

While the embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. In a variable pitch propeller, the combination including, a hub having an annular extension at the rear thereof, a stationary support, bearing means carried by said support and rotatably journalling the hub extension therein, a ring encircling said hub extension and connected to rotate therewith although capable of axial movement relative thereto, a regulator assembly connected to the front of said hub for rotation therewith, shaft means extending axially from said regulator assembly through said hub and into said hub extension, said shaft means being connected to rotate with said hub and also supported for rotation about its own axis relative to said hub, a control member disposed within said regulator assembly for rotation therewith and having a threaded connection with said shaft means whereby rotation of said shaft means imparts axial movement to said control member, means extending through said hub extension operatively interconnecting said ring and said shaft means for converting axial movement of said ring to rotation of said shaft means, and a control lever operatively connected to said ring for imparting axial movement thereto.

2. Control mechanism for a variable pitch propeller of the type having a hub with an annular extension at the rear thereof, a stationary support, bearing means carried by said support and rotatably journalling the hub extension therein and a regulator assembly attached to the front of said hub and rotatable therewith, including in combination, a ring encircling said hub extension and connected for rotation therewith although capable of axial movement relative thereto, means operatively connected to said ring for imparting axial movement thereto, shaft means extending from said regulator through said hub and into said hub extension, means operatively connecting said ring with said shaft means whereby axial movement of said ring will impart rotation to said shaft means relative to said hub, and means disposed within said regulator and operatively connected with said shaft means for performing a control function in response to rotation of said shaft means about its axis.

3. In a variable pitch propeller, the combination including, a hub having an annular extension at the rear thereof, a stationary support, bearing means carried by said support and rotatably journalling the hub extension therein, a plurality of axially spaced rings encircling said hub extension and connected to rotate therewith although capable of independent axial movement relative thereto, a regulator assembly connected to the front of said hub for rotation therewith, a plurality of shaft means equal in number to the number of said rings and extending axially from said regulator assembly through said hub and into said hub extension, said shaft means being connected to rotate with said hub and also supported for rotation about their respective axes relative to said hub, a plurality of control members equal in number to the number of said shaft means disposed within said regulator for rotation therewith, each control member having threaded connection with one of said shaft means whereby rotation of its respective shaft means imparts axial movement to one of said control members, means extending through said hub extension and operatively connecting each of said rings with one of said shaft means for converting axial movement of each ring to rotation of its respective shaft means, and means operatively connected to said rings for imparting axial movement thereto.

4. In a variable pitch propeller, the combination including, a hub having an annular extension at the rear thereof, a stationary support, bearing means carried by said support and rotatably journalling the hub extension therein, said hub extension having straight spline teeth thereon, a ring encircling said hub extension and having straight spline teeth engaged with the straight spline teeth of said hub extension whereby said ring is connected to rotate with said hub extension although capable of axial movement relative thereto, a regulator assembly connected to the front of said hub for rotation therewith, shaft means extending axially from said regulator assembly through said hub and into said hub extension, said shaft means being connected to rotate with said hub and also supported for rotation about its own axis relative to said hub, means extending through said hub extension operatively interconnecting said ring and said shaft means for converting axial movement of said ring to rotation of said shaft means, and means carried by said stationary support and engaging said ring for imparting axial movement thereto.

5. In a variable pitch propeller, the combination including, a hub having an annular extension at the rear thereof, a stationary support, bearing means carried by said support and rotatably journalling the hub extension therein, said hub extension having external straight spline teeth, a plurality of rings encircling said hub extension and having internal straight spline teeth mating with the external straight spline teeth on said hub extension, a regulator assembly connected to the front of said hub for rotation therewith, a plurality of shaft means equal in number to the number of said rings and extending axially from said regulator assembly through said hub and into said hub extension, and means extending through said hub extension and operatively connecting each ring to one of said shaft means whereby axial movement of each control ring will impart rotation to its respective shaft means relative to said hub.

6. The combination set forth in claim 5 including three axially spaced control rings, each control ring having a plurality of circumferentially spaced axially extending fingers disposed in nesting relation with the fingers of the other two rings, each finger having straight spline teeth mating with the straight spline teeth on said hub extension.

7. The combination set forth in claim 6 wherein one finger on each of said rings has a toothed edge constituting a rack.

8. The combination set forth in claim 7 wherein the means connecting each ring to its respective shaft means comprises a pinion gear disposed externally of said hub extension and engaging one of said racks, a shaft attached to said pinion gear and extending radially through said hub extension, and a pair of bevel gears disposed within said hub extension, one of said bevel gears being connected to said pinion shaft and the other bevel gear being "connected to said shaft means.

9. Control mechanism for a variable pitch propeller of the type having a hub with an annular extension at the rear thereof, a stationary support, bearing means carried by said support for rotatably journalling the hub extension therein and a regulator assembly attached to the front of said hub and rotatably therewith, including in combination, a plurality of spaced rings encircling said hub extension and having straight spline connections therewith so as to be capable of axial movement relative thereto, a plurality of shaft means equal in number to the number of said rings extending from said regulator through said hub and into said hub extension, and means extending through said hub extension and connecting each ring with one of said shaft means whereby axial movement of each ring will impart rotation to its respective shaft means relative to said hub.

10. The combination set forth in claim 9 wherein said last recited means includes a rack integral with each ring, pinion means supported externally of said hub extension and engaging said racks, each pinion gear being connected to a shaft extending radially through said hub extension, and bevel gear means connecting each pinion shaft with its respective shaft means.

References Cited in the file of this patent UNITED STATES PATENTS 

